


Mating Behavior

by wellthatjusthappend



Series: Merfolk AU [5]
Category: Batman - All Media Types
Genre: Alternate Universe - Merpeople, Anal Fingering, Blood Kink, Cultural Differences, Exploration, Fluff and Smut, Hand Jobs, Jason and Tim's first time, Jason's POV, M/M, Mer Biology, MerMay, Minor Violence, at last, ish? Mer are just sort of like that, learning each other, set between Pretty Vicious and Unforgivable
Language: English
Status: Completed
Published: 2020-05-03
Updated: 2020-05-03
Packaged: 2021-03-02 02:48:47
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,475
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23987653
Author URL: https://archiveofourown.org/users/wellthatjusthappend/pseuds/wellthatjusthappend
Summary: Jason had never seen something like his Little Bird. Humans weren’t like that, they just weren’t.But Robin… Robin was alright.
Relationships: Tim Drake/Jason Todd
Series: Merfolk AU [5]
Series URL: https://archiveofourown.org/series/779643
Comments: 17
Kudos: 288





	Mating Behavior

**Author's Note:**

> I swear I don't _mean_ to only update this series during MerMay, but... it is pretty good incentive to work on my Mer WIPs.
> 
> I've had bits of Jay and Tim's first time written for a while, so I decided to finally throw something together. They continue to be the best balanced Mer/Human couple. So much sweetness, tender violence, and smut between them.

Humans were cruel. 

Jason had known that since he was hatchling, starving for food because the humans overfishing and pollution. 

He knew it even better later when they caught him with their nets and pulled him from the sea, just to gawk at. In the beginning, he’d assumed it was some bizarre intro to Victors Rights, but it had nothing to do with honor or status or declaring a relationship. 

Jason was moved from too small tank to too small tank. His new “owners” doing nothing to prove their worth to him or right to keep him in such undignified surroundings. No, they poked and prodded, stared or ignored him as they wished. He was given cold lifeless food to eat. Some even tried to bait him into doing tricks for them like some sort of kept pet. 

And then there were those fews with more carnal interests for him. He tended to make those people _bleed,_ though never as much as he wished. 

His conclusion was: humans were cruel and unworthy. They saw themselves as victors over the world without ever trying to prove themselves. They took and took and what they gave back was harm. They had no honor and acted out victors rights without ever allowing any sort of reciprocation. 

Then he’d met Robin. 

The human and his dark Warrior master were unlike any humans Jason had ever seen. They were… noble. They hurt where it was righteous, but never in excess. The Bat-man and his Robin bird. He watched Roman threaten and rage about them for hours because of the way they would continually sabotage his cruel plans. Jason liked them long before he saw the beautiful violence of their fighting that night so long ago when Robin had been thrown into his tank. 

And the Bat Warrior- when he’d safely returned his bird to the air- had thanked him in one of the more common tongues of the Pacific Mer. His accent was terrible and it sounded wrong in the open air- not to mention, Jason was an Atlantic Mer from the trenches off Puerto Rico- but a human had never even attempted to show that sort of proper respect or gratitude towards him, so Jason simply nodded and responded in kind. 

He hadn’t expected the bird to sneak back to see him after that, but he had and Jason found himself becoming powerfully fond of the human. 

At first they just talked for hours at the opening of Jason’s tank, and Robin would bring Jason things from the outside world to stave off his boredom in captivity. He knew Robin wanted to tell him his real name, but Jason made him promise not to, knowing that Roman often watched them and would only use it against the bird. 

Jason had no idea why the nasty human just watched instead of calling the guards, but he didn’t trust him one bit so he would try to usher his bird away whenever he noticed him there. 

Eventually though, Robin started to venture into his tank with him again, equipped now with a rebreather and some basic signs between them. 

Jason had little in the way of stimulation these days- aside from the occasional human Roman would throw into his tank for execution- so these times with Robin quickly became extremely precious to him. 

He asked Robin to show him how human’s fought in the water, and Robin seemed pleased to do just that.

Robin fought him fair and square. Or perhaps fighting was the wrong word since neither of them had chosen to take victors rights thus far. No, Robin _played_ with him and loved it when Jason responded. Jason had not had simple uncomplicated fun since he was a hatchling. It made him feel young and free and wonderful in ways he hadn’t thought possible while he was still in captivity. 

“Batman and I are trying to figure out a way to get you out of here,” Robin promised, “It’s hard though, what with you being so high off the ground _and_ in one of Roman’s central bases. And Gotham Bay is a bit of a drive to get to from this part of town. You’re going to need water way before that, which means we need some sort of temporary tank- we’ve got a few for Dick but you’re bigger than him so I don’t know-”

Jason listened with interest, but honestly he didn’t care too much about the details of _how_ they would get him out, just that they would. And Jason believed in them. They might be human, but Robin and the Bat Warrior were… worthy. 

It made something go tight and wonderful inside him. For the first time, Jason started to want Robin to take Victors Rights after one of their fights. 

He never did, but sometimes he’d _flush_ so darkly when he’d notice Jason’s interest that he thought maybe he might like to as well. 

Still, he was pretty happy to keep playing together, learning how to fight with or against a human opponent. 

_Again_ , Jason signed, frowning. It shouldn’t _be_ that difficult; he was a lot stronger and faster than Robin in the water, and yet… he’d never struggled so much in a fight with a human without them cheating somehow. 

_Like this_ , Robin motioned, showing Jason the little twisted to the foot he’d done that’d thrown off Jason’s movement so much. Mer’s didn’t fight like that. Atlantians might though, since they had feet. Jason had never fought one. 

Feet were freaking weird. Especially toes. Why have something so delicate and useless that only offered minimal balance at best? Legs though… Jason liked legs. They were like little levers, the angels changing their reach and power in ways that always caught Jason off guard. He had assumed they’d be just like arms, but on the lower body. They definitely were not. They were so different from what he knew, but he liked the length and muscle to them and the way he could feel the danger against his hands.

No to mention the confused delight he experienced whenever Robin would wrap them around him and hold him in place.

...maybe he just liked _Robin’s_ legs.

Robin let Jason touch his leg while he did the kick again in slow motion, letting him run his hand over him to feel the way the muscle groups tensed and relaxed, and the quick-fire signing he did explaining about what the Mer anatomical equivalents might be.

Then suddenly Robin was grabbing Jason’s wrist, his face flushed. Jason looked and saw that the hand Robin was holding had come to rest in between his legs to stop the human from drifting while he examined the kick. 

_What?_ He signed in confusion. That only seemed to fluster Robin more.

 _You shouldn’t_ _touch me there,_ Robin signed quickly, _that’s… a mating place. For humans._

Jason was absolutely thrilled.

 _Really?_ Jason asked. 

Robin nodded. 

_Oh good,_ Jason smiled happily, _may I still touch you there?_

If Jason had thought Robin was flushed before, it was nothing compared to what he was now. Jason could feel the heat from the blood rising to his cheeks in the water and it was lovely. 

Slowly, Robin nodded again, his hand letting go of Jason’s wrist to hold onto his shoulder instead, his legs parting hesitantly for Jason to have better access. 

Jason was thrilled, this time carefully feeling out the space between his legs the way he’d never gotten to do with a human before. The armor was in the way, so after a little bit off feeling around, Robin helped him pull it and his pants down a bit and out of the way. 

The Mer had not expected him to be fully extended and hard for him, but he was not the least bit displeased. He cupped him eagerly, and felt the human in his arms shiver in response. 

In this, Jason assumed their basic biology was the same, so he quickly began to touch him the way he might touch himself, and sure enough Robin jerked and moaned long and sweetly in his arms. 

He tried to go behind his cock to his entrance, but he couldn’t find it, just these weird dangly bits of flesh. He felt them curiously, and Robin jerked in his arms, one leg kicking out almost reflexively. The extra thickness Robin’s taste in the water suggested that it was another good place though. Jason fondled the place a little longer, just to watch Robin's expression go unfocused and desperate. There was such... vulnerability in his expression, Jason wasn't sure what to do with. He hadn't even proven himself to Robin. Maybe that initial rescue counted for more than he'd thought? He wasn't sure what to do with the echoing ache and desperation that trust brought up in him. 

There _was_ an entrance a little further back. It was a tight little thing though- not that Jason was going to judge. 

He pushed in two fingers right away. He wasn’t expecting every muscle in Robin’s body to suddenly go tight as he arched and cried out with a burst of bubbles, his seed clouding the water around the hand Jason still had on his length. Jason was going to have bruises on his shoulders, he thought happily. He would have expected Robin to be slicker back there given his release, but maybe it was a human thing? He’d ask when they were above water and Robin could talk more freely. 

Jason had only really had intercourse in the context of victors rights before. And while he had definitely enjoyed that… there was a certain sweetness to this that he wasn’t at all sure what to do with. 

Perhaps… this is what it was like between mates?

Robin nuzzled against him with a softness that was confusing, but not bad, per say. It made Jason feel alike uncertain though about what was expected from him in moments like this: Mer’s were not the most cuddly creatures. 

Jason patted his back awkwardly. He got the impression that was not the correct response, given the fact that it made a burst of bubbles come out of Robin’s rebreather as his shoulders shook with silent laughter. Not the worst reaction though either. 

_Now you?_ Robin asked, wiggling a bit to get his pants back up. 

Jason nodded eagerly, and he knew that the tug of muscles around his cheeks meant that Robin was smiling back at him behind his mask with a slightly predatory look that set Jason’s blood alight. 

Unlike Jason, Robin seemed to be a lot more familiar with Mer anatomy and he had no difficulty finding the slit in his scales. He tilted his head in question again, though Jason wasn’t sure for what so he pressed Robin’s hand to him more firmly. That made the heat rise to the human’s cheeks again, but he nodded absently, seeming riveted now by the head of Jason’s cock that was just starting to extend. 

Jason shuddered hard at the feel of those gauntlets and their rough texture brushing against such a sensitive place. Robin seemed to make the connection and quickly pulled off one of his gloves and stuffed it in his belt. 

Jason wasn’t sure if he wanted to ask him to put it on again. Maybe another time. 

In the meantime, Jason bared his teeth and hissed in pleasure as Robin coaxed his shaft out with light teasing touches that he thought might drive him crazy. Once he was fully extended, Robin squeezed him firmly making Jason shudder and started and a slow but firm pace, adjusting his technique as he studied Jason’s reactions closely. 

He had the impression he was being learned at speed. Jason didn’t know quite what to do with such dedication, such obvious devotion to his pleasure and only his pleasure. He’d never thought to even want something like that, even from a future mate. Now that he had it…

It made him dizzy. It made him hungry in ways that had nothing to do with food. It made him want to lay Robin out and do him again so he could show the same devotion. But most of all it made him want to cum. 

Jason wanted to sign to Robin that he wanted his fingers in him as well as on him, but he couldn’t seem to let go of his hold on the human, so he simply hissed out fervent praises and filthy desires in his own tongue, wishing the Robin understood yet somewhat grateful he didn’t. Jason’s sharp nails clutched at his little bird instead, piercing his armor slightly and making Robin tighten his hold. 

The barest flavor of blood mixed with the taste of their mating in the water sent Jason over the edge.

Jason’s chest heaved as aftershocks of pleasure danced over his skin. Robin was watching him with awed hunger, and Jason felt himself flushing bashfully, before bumping their foreheads together affectionately and nipping at the skin under his mask.

Robin smiled happily behind his mask, before pulling it down to hesitantly nip Jason back. 

Jason shivered and felt himself twitch with interest again.

In the darkness outside the tank, he caught the barest hint of movement which meant that Roman was there again. Jason bared his teeth in hatred and irritation. He knew the bastard hated his little bird, had obviously been hoping Jason would kill him when he’d first thrown him in his tank back when they’d first met. Jason didn’t want the evil man anywhere near his bird. 

That meant that they would need to part though. 

Robin gave him a questioning look at Jason’s sudden change in mood, but Jason just shook his head and pulled them to the surface. 

“The humans here will start to gather soon,” Jason told him unhappily, “You will need to fly now before they try to catch you.”

“Oh, I see,” Robin also looked disappointed. He hesitated though and Jason looked up at him only to get the softest kiss on his mouth. 

_“It’s mating behavior_ ,” Robin had told him back when he was first explaining why he would wear a mask rather than let Jason just breathe into him when they were underwater.

Excitement stirred in Jason’s veins as he pressed back. Did that mean that Robin wanted to be his mate too? 

“I’ll come back soon,” Robin said shyly when they parted. 

“Do not stay away long,” Jason said, bumping his mouth against the other’s again, trying to convey his feelings in a way the other would understand. 

“As soon as it’s safe,” Robin promised, giving him one last lingering kiss before drawing back and flying away. 

Jason watched him go and dreamed of the day they could be together truly and he could be free.

**Author's Note:**

> I was thinking that I'd just fill Mer related prompts and stories this month, but I keep getting sent such interesting other ones! I guess we'll see what happens.


End file.
